The long term goal of this project is to develop a biomarker - the Needle Torque Test (NTT) - capable of detecting connective tissue abnormalities associated with musculoskeletal disorders. The NTT is administered by inserting an acupuncture needle into connective tissue and using the Automated Needle Torque Sensor to deliver a precise biomechanical stimulus to the needle probe via rotation. The tissue response to this stimulus is quantified as torque. Our Specific Aims are: 1) Document Automated Needle Torque Sensor device and Needle Torque Test procedural reliability in vitro. This will be achieved by making structural and methodological refinements designed to insure measurement consistency, and documenting device performance under simulated clinical conditions against known torques. 2) Document the Needle Torque test/retest reliability in vivo. To fulfill this aim, we will perform a longitudinal study in 100 healthy human subjects without musculoskeletal pain or pathology, repeating testing of 6 points on the biceps femoris, rectus femoris, and biceps brachii at three time points (time 0, 30 minutes and 1 week). 3) Validate the NTT as a biomarker capable of identifying connective tissue abnormalities by: a) establishing an NTT/connective tissue disorder link. We will collect and compare NTT scores in 15 subjects with scleroderma, and 15 subjects with inherited connective tissue disorders manifesting as connective tissue hyperlaxity, compared with 30 control subjects from Aim 2 that are frequency-matched for age and sex and b) establishing an NTT/musculoskeletal disorder link. We will collect and compare NTT scores in 15 subjects with restricted hamstring flexibility, compared with 15 control subjects from Aim 2 with normal hamstring flexibility who have been frequency-matched for age and sex. PUBLIC HEALTH RELEVANCE: Chronic musculoskeletal pain is the source of considerable disability, work absenteeism and health care costs. A major obstacle to the incorporation of manual therapies such as massage and spinal manipulation into our health care system is the lack of methods to objectively measure the effect of treatments. Automated Needle Torque Sensor technology under development in this project will potentially enable objective measurement of connective tissue abnormalities associated with musculoskeletal pain. This will 1) help establish the efficacy of manual treatments through improved research, 2) enhance the objective monitoring of patient progress in clinical practice and 3) bolster the evidence needed to justify insurance reimbursement.